A conventional power-distribution unit (PDU) is an assembly of multiple electrical “outlets” (also called “receptacles”) that receive electrical power from a source and distribute the electrical power via the outlets to one or more separate electronic equipment units having respective power cords plugged into respective outlets of the PDU. PDUs can be used in any of various applications and settings such as, for example, in or on a rack used for housing and supporting various pieces of electronic equipment.
Certain types of PDUs support remote control of one or more of their respective outlets. This remote control can be accomplished by, for example, by a remote computer communicating through a network with the PDU. Examples of remotely controllable PDUs include products made and distributed by Server Technology, Inc., of Reno, Nev.
One such prior art Server Technology product is the Sentry CDU™ PDU system 100, shown in FIGS. 1A and 1B. The SENTRY CDU PDU includes multiple ganged-outlet modules 102, with each ganged-outlet module having multiple receptacles (outlets) 104 such as IEC C13 receptacles. Each ganged-outlet module 102 includes seven receptacles 104 arranged linearly in a ganged-outlet housing 106 mounted vertically in the PDU system 100 as shown in the FIGS. Each receptacle 104 includes a female ground socket 108, a female neutral socket 110, and a female line (“hot”) socket 112. As shown in FIG. 1B, in each ganged-outlet housing 106, all ground sockets 108 are interconnected by a common linear ground rail 114; all neutral sockets 110 are interconnected by a common linear neutral rail 116 parallel to the ground rail 114, and all line sockets 112 are interconnected by common linear line rail 118 also parallel to the ground rail 114. Accordingly, corresponding sockets of adjacent outlets of each ganged-outlet module share a common rail and are not individually controllable.
As shown in FIGS. 1A and 1B, the power rails 114, 116, 118 are external to the respective housings 106. As a result of their external placement, in certain environments, the power rails are exposed to other structure in the vicinity of the power rails. In some applications, the power rails may be vulnerable to unintentional contact with and/or disruption by other components inside the PDU system 100. Whenever multiple ganged-outlet modules 102 are mounted in a housing 120, such as shown in FIGS. 1A-1B, the exposed power rails 114, 116, 118 typically are separated electrically from other components within the housing 120 by means of flexible insulative polymeric sheeting. Thus, in certain embodiments of this type of PDU system 100, the exposed power rails 114, 116, 118 require use of extra insulating material within the PDU system 100. In such embodiments, mis-assembly of the PDU system 100 at time of manufacture or incorrect re-assembly after making a repair to the PDU system 100 may present a risk of electrical shorts.
In addition, the ganged-outlet modules 102 of FIGS. 1A and 1B accommodate only conventional two- or three-pronged connectors such as the IEC C13 receptacles 104 shown. As a result, these types of prior art receptacles typically do not accommodate other types of connectors, such as NEMA connectors.
One conventional PDU system 230 having NEMA compatible receptacles is a Server Technology PDU-VL16™ system, as shown in FIG. 2. In the PDU-VL16 system 230, the NEMA compatible receptacles 232 are not ganged, but rather are mounted and manually wired individually in the PDU housing 234. In this conventional PDU system 230, each individual NEMA receptacle 232 is separately wired to each of three power-supply lines (ground, neutral, and line) inside the housing 234. Separately manually wiring each receptacle 232 can present a number of disadvantages. For example, it can make assembly of the PDU system 230 time-consuming, and thus expensive, expensive to assemble. Separately manually wiring each receptacle 232 can also make such PDU systems 230 less reliable. Also, substantial space must typically be provided inside the housing 234 for each of the receptacles 232, their mounting structures, and their respective wiring.